Method and system for network communications via a configurable multi-use ethernet PHY

ABSTRACT

Aspects of a method and system for network communications via a configurable multi-use Ethernet PHY are provided. In this regard, an Ethernet PHY may be configured based on characteristics of a network link over which the Ethernet PHY communicates, and a rate at which data is conveyed from a MAC to the Ethernet PHY may be controlled via a carrier sense signal of the MII. The carrier sense signal may be controlled based on a rate at which the Ethernet PHY transmits data over the network link. The Ethernet PHY may be configured based on a length of the network link and/or on a grade of the network link, where exemplary grades may comprise Cat-1 through Cat-7a cable. The Ethernet PHY may be configured into one of a plurality of modes comprising an Ethernet over digital subscriber line (DSL) mode, an extended reach mode, and a standard Ethernet mode.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

Not Applicable

FIELD OF THE INVENTION

Certain embodiments of the invention relate to networking. Morespecifically, certain embodiments of the invention relate to a methodand system for network communications via a configurable multi-useEthernet PHY.

BACKGROUND OF THE INVENTION

With the increasing popularity of electronics such as desktop computers,laptop computers, and handheld devices such as smart phones and PDA's,communication networks are becoming an increasingly popular means ofexchanging data of various types and sizes for a variety ofapplications. One set of networking technologies, namely Ethernet, hasbeen particularly successful with regard to deployment in local areanetworks (LANs) and has made networking useful and affordable toindividual and business customers of all levels and sizes. Everyday moreand more devices are being equipped with Ethernet interfaces andEthernet is increasingly being utilized to carry information of alltypes and sizes including voice, data, and multimedia. Due to theubiquity of Ethernet in LANs, the advantages of using Ethernet in widearea networks are being recognized and Efforts such as Ethernet in theFirst Mile IEEE 802.3ah seek to realize these advantages. As the role ofEthernet expands to networks of all topologies and/or technologies,however, equipment manufacturers, service providers, and networkadministrators are presented with new economic and technologicalchallenges.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with some aspects of the present invention asset forth in the remainder of the present application with reference tothe drawings.

BRIEF SUMMARY OF THE INVENTION

A system and/or method is provided for network communications via aconfigurable multi-use Ethernet PHY, substantially as shown in and/ordescribed in connection with at least one of the figures, as set forthmore completely in the claims.

These and other advantages, aspects and novel features of the presentinvention, as well as details of an illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a functional block diagram illustrating an exemplary Ethernetconnection between two network devices, which may comprise configurablemulti-use PHYs, in accordance with an embodiment of the invention.

FIG. 2A is a diagram illustrating managing data transmission via acarrier sense signal of a media independent interface, in accordancewith an embodiment of the invention.

FIG. 2B is a flow chart illustrating exemplary steps for managing datatransmission via a carrier sense signal of a media independentinterface, in accordance with an embodiment of the invention.

FIG. 3 is a functional block diagram illustrating a PHY configurablebased on characteristics of a link over which it communicates, inaccordance with an embodiment of the invention.

FIG. 4A is a diagram illustrating use of a configurable multi-use PHYfor Ethernet over DSL communications, in accordance with an embodimentof the invention.

FIG. 4B is a diagram illustrating use of a configurable multi-use PHYfor extended reach Ethernet communications, in accordance with anembodiment of the invention.

FIG. 4C is a diagram illustrating use of a configurable multi-use PHYfor standard Ethernet communications, in accordance with an embodimentof the invention.

FIG. 5A is a functional block diagram illustrating a network deviceoperable to convey data between network links having differentcharacteristics, in accordance with an embodiment of the invention.

FIG. 5B is a flow chart illustrating exemplary steps for controllingingress data flow in a network device that conveys data between networklinks having different characteristics, in accordance with an embodimentof the invention.

FIG. 5C is a flow chart illustrating exemplary steps for controllingegress data flow in a network device that conveys data between networklinks having different characteristics, in accordance with an embodimentof the invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention may be found in a method and systemfor network communications via a configurable multi-use Ethernet PHY. Invarious embodiments of the invention, a first Ethernet PHY may beconfigured based on characteristics of a network link over which thefirst Ethernet PHY communicates, and a rate at which data is conveyedfrom a first media access controller (MAC) to the first Ethernet PHY viaa media independent interface (MII) may be controlled via a carriersense signal of the MII. The carrier sense signal may be controlledbased on a rate at which the first Ethernet PHY transmits data over thenetwork link. The rate at which the first Ethernet PHY transmits dataover the network link may be determined by monitoring a queue thatbuffers data to be transmitted. The carrier sense signal may be assertedwhen an amount of data stored in the queue is above a threshold. Thecarrier sense signal may be de-asserted when the amount of data storedin the queue is below a threshold. The first Ethernet PHY may beconfigured based on a length of the network link. The first Ethernet PHYmay be configured based on a grade of the network link, where exemplarygrades may comprise Cat-1 through Cat-7a cable. The first Ethernet PHYmay be configured into one of a plurality of modes comprising anEthernet over digital subscriber line (DSL) mode, an extended reachmode, and a standard Ethernet mode. The MII may comprise one of a mediaindependent interface (MII), a gigabit MII (GMII), a reduced MII (RMII),reduced gigabit MII (RGMII), and 10 gigabit MII (XGMII).

In some embodiments of the invention, the first Ethernet PHY, the firstMAC, a second Ethernet PHY, and a second MAC may be integrated within anetwork device. In such embodiments, data may be received by the secondEthernet PHY, buffered in a queue, and transmitted by the first EthernetPHY, where the second Ethernet PHY receives the data at a rate that maybe different than the rate at which the first Ethernet PHY transmits thedata. In some instances, the second Ethernet PHY may be operable torequest that a link partner pause or slow down transmission of databased on a status of the queue.

FIG. 1 is a functional block diagram illustrating an exemplary Ethernetconnection between two network devices, which may comprise configurablemulti-use PHYs, in accordance with an embodiment of the invention.Referring to FIG. 1, there is shown a system 100 that comprises anetwork device 102 and a network device 104. The network devices 102 and104 may be link partners that communicate via the link 112 and maycomprise, respectively, hosts 106 a and 106 b, networking subsystems 108a and 108 b, PHY 110 a and 110 b, interfaces 114 a and 114 b, interfaces116 a and 116 b, and interfaces 118 a and 118 b. The interfaces 114 aand 114 b are referenced collectively or separately herein asinterface(s) 114, and the interfaces 116 a and 116 b are referencedcollectively or separately herein as interface(s) 116. The hosts 106 aand 106 b are referenced collectively or separately herein as host(s)106. The networking subsystems 108 a and 108 b are referencedcollectively or separately herein as networking subsystem(s) 108. ThePHY 110 a and 110 b are referenced collectively or separately herein asPHY(s) 110.

The link 112 is not limited to any specific medium. Exemplary link 112media may comprise copper, wireless, optical and/or backplanetechnologies. For example, a copper medium such as STP, Cat3, Cat 5, Cat5e, Cat 6, Cat 7 and/or Cat 7a as well as ISO nomenclature variants maybe utilized. Additionally, copper media technologies such as InfiniBand,Ribbon, and backplane may be utilized. With regard to optical media forthe link 112, single mode fiber as well as multi-mode fiber may beutilized. With regard to wireless, the network devices 102 and 104 maysupport one or more of the 802.11 family of protocols. In variousembodiments of the invention, the network device 102 and the networkdevice 104 may communicate via two or more physical channels comprisingthe link 112. For example, Ethernet over twisted pair standards 10BASE-Tand 100BASE-TX may utilize two pairs of UTP while Ethernet over twistedpair standards 1000BASE-T and 10GBASE-T may utilize four pairs of UTP.

The network devices 102 and/or 104 may comprise, for example, switches,routers, end points, computer systems, audio/video (A/V) enabledequipment, or a combination thereof. Additionally, the network devices102 and 104 may be enabled to utilize Audio/Video Bridging and/orAudio/video bridging extensions (collectively referred to herein asaudio video bridging or AVB) for the exchange of multimedia content andassociated control and/or auxiliary data. Also, the network devices maybe operable to implement security protocols such IPsec and/or MACSec.

The hosts 106 a and 106 b may be operable to handle functionality of OSIlayer 3 and above in the network devices 102 and 104, respectively. Thehosts 106 a and 106 b may be operable to perform system control andmanagement, and may comprise hardware, software, or a combinationthereof. The hosts 106 a and 106 b may communicate with the networkingsubsystems 108 a and 108 b via interfaces 116 a and 116 b, respectively.The hosts 106 a and 106 b may additionally exchange signals with thePHYs 110 a and 110 b via interfaces 118 a and 118 b, respectively. Theinterfaces 116 a and 116 b may correspond to PCI or PCI-X interfaces.The interfaces 118 a and 118 b may comprise one or more discrete signalsand/or communication busses. In various embodiments of the invention,one or both of the hosts 106 may comprise one or more queues 115 _(Z)for buffering received and/or to-be-transmitted data.

The networking subsystems 108 a and 108 b may comprise suitable logic,circuitry, and/or code that may be operable to handle functionality ofOSI layer 2 and above layers in the network device 102 and 104,respectively. In this regard, networking subsystems 108 may eachcomprise a media access controller (MAC) and/or other networkingsubsystems. Each networking subsystem 108 may be operable to implementswitching, routing, and/or network interface card (NIC) functions. Eachnetworking subsystems 108 a and 108 b may be operable to implementEthernet protocols, such as those based on the IEEE 802.3 standard, forexample. Notwithstanding, the invention is not limited in this regard.The networking subsystems 108 a and 108 b may communicate with the PHYs110 a and 110 b via interfaces 114 a and 114 b, respectively. Theinterfaces 114 a and 114 b may correspond to Ethernet interfaces thatcomprise protocol and/or link management control signals such as acarrier sense signal (CRS). The interfaces 114 a and 114 b may be, forexample, multi-rate capable interfaces and/or media independentinterfaces (xxMII). In this regard, “media independent interface (MII)”is utilized generically herein and may refer to a variety of interfacessuch as a media independent interface (MII), a gigabit MII (GMII), areduced MII (RMII), reduced gigabit MII (RGMII), and 10 gigabit MII(XGMII). In various embodiments of the invention, one or both of thenetworking subsystems 108 may comprise one or more queues 115 _(Y) forbuffering received and/or to-be-transmitted data.

The PHYs 110 may each comprise suitable logic, circuitry, interfaces,and/or code that may enable communication between the network device 102and the network device 104. Each of the PHYs 110 may be referred to as aphysical layer transmitter and/or receiver, a physical layertransceiver, a PHY transceiver, a PHYceiver, or simply a PHY. The PHYs110 a and 110 b may be operable to handle physical layer requirements,which include, but are not limited to, packetization, data transfer andserialization/deserialization (SERDES), in instances where such anoperation is required. Data packets received by the PHYs 110 a and 110 bfrom networking subsystems 108 a and 108 b, respectively, may includedata and header information for each of the above six functional OSIlayers. The PHYs 110 a and 110 b may be configured to convert packetsfrom the networking subsystems 108 a and 108 b into physical layersignals for transmission over the physical link 112, and convertreceived physical signals into digital information. In some embodimentsof the invention, the PHYs 110 may comprise suitable logic, circuitry,and/or code operable to implement MACSec. In various embodiments of theinvention, one or both of the PHY devices 110 may comprise one or morequeues 115 _(X) for buffering receiving and/or to-be-transmitted data.

One or both of the PHYs 110 may comprise a twisted pair PHY capable ofoperating at one or more standard rates such as 10 Mbps, 100 Mbps, 1Gbps, and 10 Gbps (10BASE-T, 100GBASE-TX, 1GBASE-T, and/or 10GBASE-T);potentially standardized rates such as 40 Gbps and 100 Gbps; and/ornon-standard rates such as 2.5 Gbps and 5 Gbps. One or both of the PHYs110 may comprise a backplane PHY capable of operating at one or morestandard rates such as 10 Gbps (10GBASE-KX4 and/or 10GBASE-KR); and/ornon-standard rates such as 2.5 Gbps and 5 Gbps. One or both of the PHYs110 may comprise an optical PHY capable of operating at one or morestandard rates such as 10 Mbps, 100 Mbps, 1 Gbps, and 10 Gbps;potentially standardized rates such as 40 Gbps and 100 Gbps; and/ornon-standardized rates such as 2.5 Gbps and 5 Gbps. In this regard, theoptical PHY may be a passive optical network (PON) PHY. One or both ofthe PHYs 110 may support multi-lane topologies such as 40 Gbps CR4, ER4,KR4; 100 Gbps CR10, SR10 and/or 10 Gbps LX4 and CX4. Also, serialelectrical and copper single channel technologies such as KX, KR, SR,LR, LRM, SX, LX, CX, BX10, LX10 may be supported. Non-standard speedsand non-standard technologies, for example, single channel, two channelor four channels may also be supported. More over, TDM technologies suchas PON at various speeds may be supported by the PHYs 110.

Also, the PHYs 110 may support transmission and/or reception at ahigh(er) data in one direction and transmission and/or reception at alow(er) data rate in the other direction. For example, the networkdevice 102 may comprise a multimedia server and a link partner maycomprise a multimedia client. In this regard, the network device 102 maytransmit multimedia data, for example, to the link partner at high(er)data rates while the link partner may transmit control or auxiliary dataassociated with the multimedia content at low(er) data rates. Thenetwork device 102 may also support wireless protocols such as the IEEE802.11 family of standards.

Each of the PHYs 110 a and 110 b may be operable to implement one ormore energy efficient techniques, which may be referred to as energyefficient networking (EEN), or in the specific case of Ethernet, energyefficient Ethernet (EEE). For example, the PHYs 110 a and 110 b may beoperable to support low power idle (LPI) and/or subrating techniques,such as subset PHY for Copper based PHYs. LPI may generally refer afamily of techniques where, instead of transmitting conventional IDLEsymbols during periods of inactivity, the PHYs 110 a and 110 b mayremain silent and/or communicate signals other than conventional IDLEsymbols. Subrating may generally refer to a family of techniques wherethe PHYs are reconfigurable, in real-time or near real-time, tocommunicate at different data rates.

In operation, For example, in some instances, data may be communicatedfrom the network device 102 to the network device 104 over the link 112.In such instances, the networking subsystem 108 a may communicate datavia the interface 114 a to the PHY 110 a at a higher rate than the linerate, or other specified rate, at which the PHY 110 a may operable tooutput the data onto the link 112. That is, the networking subsystem 108a and the PHY 110 a may be mismatched with regard to an egress datarate. Consequently, a queue, such as one or more of the queues 115, thatstore the egress data may eventually overflow. Accordingly, the rate atwhich the PHY 110 a is transmitting data and/or an amount of datawaiting to be transmitted may be monitored and the PHY 110 a may notifythe networking subsystem to hold off sending more data to the PHY 110 auntil the PHY 110 a is ready to receive more data without dropping orcorrupting any data. In various embodiments of the invention, the PHY110 a may notify the MAC 108 a via the CRS 120 a and/or by generatingone or more pause frames and conveying the pause frames up to thenetworking subsystem 108 a via a receive path of the interface 114 a.

In various embodiments of the invention, the CRS 120 a may be controlledto match the rate at which data comes into the PHY 110 a from thenetworking subsystem 108 with the rate at which the data is transmittedonto the link 112. In this regard, the PHY 110 a may assert the CRS 120a during periods when the PHY 110 a cannot handle additional data fromthe networking subsystem 108 a. For example, the PHY 110 a may be unableto handle additional data from the networking subsystem 108 a when it isalready transmitting data onto the link 112 at the line rate, or otherspecified maximum rate. The networking subsystem 108 a may, accordingly,defer transmission until the PHY 110 a de-asserts the CRS 120 a. The PHY110 a may de-assert the CRS 120 a when the PHY 110 a can handleadditional data from the networking subsystem 108 a. For example, thePHY 110 a may be able to handle data from the networking subsystem 108when the rate at which the PHY 110 a communicates data onto the link 112drops below the line rate, or other specified rate.

In various embodiments of the invention, the PHY 110 a may generate oneor more pause frames and convey the pause frames up to the networkingsubsystem 108 a during periods when the PHY 110 a cannot handleadditional data to be transmitted. For example, the PHY 110 a may beunable to handle additional data from the networking subsystem 108 awhen it is already transmitting data onto the link 112 at the line rate,or other specified maximum rate. Once the PHY 110 a is ready to receivedadditional data from the networking subsystem 108 it may generate anunpause frame and convey the unpause frame up to the networkingsubsystem 108 a. The pause and unpause frames may be sent to thenetworking subsystem 108 as if they were frames received from a linkpartner. Accordingly, the networking subsystem 108 a may be operable toinspect received frames and distinguish pause and unpause frames fromother received data. The networking subsystem 108 a may hold-offconveying data to be transmitted to the PHY 110 a during periods of timebetween receiving a pause frame and receiving a corresponding unpauseframe. An unpause frame may, for example, comprise a pause frame with await time field set to 0. Additionally or alternatively, an MAC mayresume sending data to the PHY upon expiration of a timer without havingreceived an unpause frame.

In some embodiments of the invention, one or more queues in which theegress data is buffered may be monitored to determine whether the PHY110 a is ready to receive data from the networking subsystem 108 a. Forexample, in instances that a queue 115 in which the egress data isstored reaches a threshold, the PHY 110 a may assert the CRS 120 aand/or generate a pause frame to pause or slow down the data beingoutput by the networking subsystem 108 a. Upon the occupied portion ofthe queue 115 dropping below a particular threshold, the PHY 110 a mayde-assert the CRS 120 a and/or generate an unpause frame and, upondetecting the de-assertion of the CRS 120 a and/or the receipt of theunpause frame, the networking subsystem 108 a may resume sending data tothe PHY 110 a via the interface 114 a.

In various embodiments of the invention, the Ethernet PHYs 110 may beconfigured based on characteristics of the link 112. The configurationof the PHYs 110 may, in turn, determine the rate at which the PHYs 110are operable to communicate over the link 112. Exemplary characteristicsof the link 112 factored into the configuration may comprise the lengthand/or grade or quality of the link 112. For example, in a local areanetwork (LAN) the link 112 may comprise up to 100 meters of CAT-5 UTP,whereas in an Ethernet over DSL application, the link 112 may compriseup to 2.7 km of CAT-1 UTP.

Controlling the flow of traffic between a MAC and PHY utilizing the CRS120 may thus enable utilizing a single configurable PHY device invarious applications. Moreover, utilizing the CRS to control the dataflow may enable the configurable multi-use PHY 110 to interface to alegacy MAC, regardless of whether that MAC communicates full-duplex orhalf-duplex, and regardless whether the MAC was designed forcommunication over high quality UTP at less than 100 meters, such as the10/100/1G/10GBASE-T protocols, or for communication over lower grade UTPand/or longer links, such as the 10PASS-TS or 2BASE-TL protocols. Thatis, a multi-use configurable PHY 110 may be compatible with MACsdesigned for LAN applications, Ethernet over DSL applications, and otherapplications.

FIG. 2A is a diagram illustrating managing data transmission via acarrier sense signal of a media independent interface, in accordancewith an embodiment of the invention. Referring to FIG. 2A there is showna networking subsystem 108, a PHY 110, a queue 115, and correspondingvalues of a CRS 120 during a sequence of time instants T1-T5.

The networking subsystem 108 may be as described with respect to FIG. 1.The PHY 110 may be the same as the PHYs 110 a and 110 b described withrespect to FIG. 1. The queue 115 may be the same as one or more of thequeues 115 _(X), 115 _(Y), and 115 _(Z) described with respect toFIG. 1. The CRS 120 may be the same as the CRS signals 120 a and 120 bdescribed with respect to FIG. 1.

At time instant T1, the queue 115 is not, or has not been, filled abovethe threshold 204. Accordingly, the CRS 120 is de-asserted and thenetworking subsystem 108 is communicating data to the PHY 110 at ahigh(er) data rate (as indicated by the large arrow 156) the PHY 110 istransmitting data onto the link 112 a low(er) rate (as indicated by thesmall arrow 158), where the rate at which the PHY 110 transmits onto thelink 112 may be determined based on characteristics of the link 112.

At time instant T2, the queue 115 may have more data buffered in it thanat time instant T1; however, the amount of data has still not surpassedthe threshold 204 and thus the CRS 120 remains de-asserted and the datacontinues to be communicated from the networking subsystem 108 to thePHY 110.

At time instant T3, the amount of data in the queue 115 has risen abovethe threshold 204 and thus the CRS 120 may be asserted and/or a pauseframe may be generated and conveyed to the networking subsystem 108. ThePHY 110 may continue to drain the queue 115 by transmitting data ontothe link 112.

At time instant T4, the PHY 110 may continue to transmit data and drainthe queue 115; however, hysteresis may be utilized to prevent rapidtoggling of the CRS 120 and thus, the CRS 120 may be de-asserted onlywhen the level of data in the queue 115 drops below the threshold 206.Accordingly, the CRS 120 may remain asserted and communication from thenetworking subsystem 108 to the PHY 110 may remain paused.

At time instant T5, the amount of data in the queue 115 may drop belowthe threshold 206, accordingly the CRS 120 may be de-asserted and/or apause frame may be generated and conveyed to the networking subsystem108 and data may again be communicated from the networking subsystem 108to the PHY 110.

FIG. 2B is a flow chart illustrating exemplary steps for managingcommunication of data from a MAC to a PHY via a carrier sense signal ofa media independent interface, in accordance with an embodiment of theinvention. Referring to FIG. 2B, from start step 222, the exemplarysteps may advance to step 224 in which it may be determined whetherthere is data pending conveyance from a MAC to a PHY via an xxMII. Ininstances that there is no to-be-transmitted data pending communicationfrom the MAC to the PHY, the steps may remain in step 224 until there isdata to be communicated to the PHY. In instances that there is datapending communicated from the MAC to the PHY, the exemplary steps mayadvance to step 226.

In step 226 it may be determined whether a CRS signal of the xxMIIbetween the MAC and PHY is asserted. In instances, that the CRS isasserted, the exemplary steps may advance to step 234.

In step 234, the MAC may hold off communication of data to the PHY untilthe PHY de-asserts the CRS. In this regard, the PHY 110 may de-assertthe CRS signal when the amount of data buffered in a transmit queuedrops below a threshold. Subsequent to step 234, the exemplary steps mayreturn to step 224.

Returning to step 226, in instances that the CRS is not asserted, theexemplary steps may advance to step 228. In step 228, the MAC maycommunicate data to the PHY. Subsequent to step 228, the exemplary stepsmay advance to step 230.

In step 230, data communicated from the MAC to the PHY may be stored ina queue and it may be determined whether the additional data in thequeue has filled the queue above a threshold. In instances that thequeue is not filled above the threshold the exemplary steps may returnto step 224. In instances that the queue is filled above the thresholdthe exemplary steps may advance to step 232.

In step 232 the PHY may assert the CRS. Subsequent to step 232, theexemplary steps may advance to step 234.

In step 234, the PHY may wait for the amount of data buffered in thequeue to be below a threshold as data is read out from the queue andtransmitted. Once the queue is below the threshold the PHY may de-assertthe CRS and the exemplary steps may return to step 224

FIG. 3 is a functional block diagram illustrating a PHY configurablebased on characteristics of a link over which it communicates, inaccordance with an embodiment of the invention. Referring to FIG. 3there is shown a PHY 310 and a MAC 308.

The PHY 310 may be similar to or the same as the PHYs 110 a and 110 bdescribed with respect to FIG. 1. The MAC 308 may be similar to or thesame as the networking subsystem 108, or a portion thereof, describedwith respect to FIG. 1. The CRS 120 may be as described with respect toFIG. 1.

The PHY 310 may comprise suitable logic, circuitry, interfaces, and/orcode that may enable the PHY 310 to be configured into various modes ofoperation. The configurability of the PHY 310 is represented by theswitching element 316 controlled by a signal 314. Additionally, asdescribed with respect to FIGS. 1, 2A, and 2B, the PHY 310 may beoperable to control the flow of data from the MAC 308 via the CRS 120and/or by generating pause frames.

The link detection and/or characterization module 318 may comprisesuitable logic, circuitry, code, and/or interfaces that may be operableto determine characteristics of the link 304 and generate the controlsignal 314 accordingly. Exemplary characteristics that may be determinedby the module 318 may comprise length, grade, and/or number of availablechannels or conductors of the link 304.

In operation, the switching element 316 may be configured to select anappropriate mode of operation for communicating over the network link304. In some embodiments of the invention, the PHY 310 may comprise themodule 318 and configuration of the PHY 310 may be controlled based onan automatic link detection and/or characterization. In otherembodiments of the invention, control signal 314, and thus configurationof the PHY 310, may be controlled via software and/or manually by anetwork administrator, application, or end-user.

FIG. 4A is a diagram illustrating use of a configurable multi-use PHYfor Ethernet over DSL communications, in accordance with an embodimentof the invention. Referring to FIG. 4A, there is shown a network device400 communicatively coupled to a broadband access network 402 and a linkpartner 408. The network device 400 comprises a controller 412, a memory414, and Ethernet PHYs 310 a and 310 b, which are operable tocommunicate over links 404 and 406, respectively.

The broadband access network 402 may be owned and/or operated by aservice provider such as a telephone company. The broadband accessnetwork 402 may provide Internet connectivity to homes and businessutilizing DSL.

The controller 412 may comprise suitable logic, circuitry, interfaces,and/or code that may be operable to process data and/or controloperations of the network device 400. With regard to processing data,the controller 412 may enable packetization, de-packetization,transcoding, reformatting, and/or otherwise processing data receivedfrom and/or to be transmitted by the network device 400. With regard tocontrolling operations of the network device 400, the controller 412 maybe enabled to provide control signals to the various other portions ofthe network device 400. In this regard, the controller 412 may beoperable to make decisions and/or generate signals for configuring theEthernet PHYs 310 a and 310 b. The controller 412 may also control datatransfers between various portions of the network device 400. Thecontroller 412 may enable execution of applications programs and/orcode. In this regard, the applications, programs, and/or code mayenable, for example, parsing, transcoding, or otherwise processing ofdata. Furthermore, the applications, programs, and/or code may enable,for example, configuring or controlling operation of the Ethernet PHYs310 a and 310 b and/or the memory 414.

The memory 414 may comprise suitable logic, circuitry, and/or code thatmay enable storage or programming of information that includesparameters and/or code that may effectuate the operation of the networkdevice 400. The parameters may comprise configuration data and the codemay comprise operational code such as software and/or firmware and theparameters may include adaptive filter and/or block coefficients, butthe information need not be limited in this regard. Additionally, thememory 400 may buffer or otherwise store received data and/or data to betransmitted. In various embodiments of the invention, the memory 400 maystore instructions, parameters, of other information for configuring theEthernet PHYs 310 a and 310 b. Each of the Ethernet PHYs 310 a and 310 bmay be the same as the PHY 310, which is described with respect to FIG.3.

In operation, the Ethernet PHYs 310 a and 310 b may be configured forcommunication over the respective links 404 and 406. In an exemplaryembodiment of the invention, the link 404 may comprise voice grade UTPdesigned and/or suited for DSL and the link 406 may comprise less than100 meters of CAT-5e UTP. Accordingly, the Ethernet PHY 310 a may beconfigured into an Ethernet over DSL mode and the Ethernet PHY 310 b maybe configured into a standard Ethernet mode. In this regard, the codingand signaling techniques utilized by the Ethernet PHY 310 a may adhereto, for example, 10PASS-TS or 2BASE-TL. In this regard, the networkdevice 400 may function as a modem, router, and/or switch to provideInternet access to devices such as the device 408. The Ethernet PHY 310b, on the other hand, may utilize coding and signaling techniques thatadhere to, for example, one of 10BASE-T, 100BASE-T, 1000BASE-T, or10GBASE-T.

The protocols and link characteristics described with regard to FIG. 4Aare for illustration purposes and the invention is not so limited. Also,the network device 400 comprises two PHYs for illustration only and adevice such as network device 400 may comprise any number of EthernetPHYs each of which may be configurable and/or may communicate overcopper, optical fiber, or backplane.

FIG. 4B is a diagram illustrating use of a configurable multi-use PHYfor extended reach Ethernet communications, in accordance with anembodiment of the invention. Referring to FIG. 4B, there is shown anetwork device 400 communicatively coupled to a broadband access network420 and a link partner 408. The network device 400, its PHYs 310 a and310 b, controller 412, and memory 414 may be as described with respectto FIG. 4A.

The broadband access network 402 may be owned and/or operated by aservice provider such as a telephone company. The broadband accessnetwork 402 may provide internet connectivity to homes and businessesutilizing Extended reach Ethernet techniques such as those described inUnited States patent application Ser. No. 61/101,072 filed on Sep. 29,2009, and United States patent application Ser. No. 12/495,496 filed onJun. 30, 2009, referenced and incorporated in paragraph [0001] above. Inthis regard, the rate at which the broadband access network 420communicates with the network device 400 may be adapted based oncharacteristics of the link 424, where exemplary characteristicscomprise a grade of the link, a length of the link, a number of channelsavailable on the link, temperature of the link, and interference presenton the link.

In operation, the Ethernet PHYs 310 a and 310 b may be configured forcommunication over the respective links 424 and 406. In an exemplaryembodiment of the invention, the link 424 may comprise more than 100meters of Cat-5e UTP and the link 406 may comprise less than 100 M ofCAT-5e UTP. Accordingly, the Ethernet PHY 310 a may be configured forextended reach Ethernet and the Ethernet PHY 310 b may be configuredinto a standard Ethernet mode. In this regard, the rate at which data iscommunicated over the link 424 and/or the number of channels of the link424 over which data is communicated may be configured based on thecharacteristics of the link 424. Adjusting the data rate ofcommunications on the link 424 may compensate, for example, for theincreased delay, noise, and/or attention of the link 424. In thisregard, the network device 400 may function as a modem, a switch, and/ora router to provide Internet access to devices such as the device 408.The Ethernet PHY 310 b, on the other hand, may communicate over the link406 may at a standard rate as defined by, for example, 10BASE-T,100BASE-T, 1000BASE-T, or 10GBASE-T.

The protocols and link characteristics described with regard to FIG. 4Bare for illustration purposes and the invention is not so limited. Forexample, both links may be longer than 100M and both Ethernet PHYs 310 aand 310 b may be configured into an Extended reach mode. Also, thenetwork device 400 comprises two PHYs for illustration only and a devicesuch as network device 400 may comprise any number of Ethernet PHYs eachof which may be configurable and/or may communicate over copper, opticalfiber, or backplane.

FIG. 4C is a diagram illustrating use of a configurable multi-use PHYfor standard Ethernet communications, in accordance with an embodimentof the invention. Referring to FIG. 4B, there is shown a network device400 communicatively coupled to a link partner 432 and a link partner408. The network device 400, its PHYs 310 a and 310 b, controller 412,and memory 414 may be as described with respect to FIG. 4A.

In operation, the Ethernet PHYs 310 a and 310 b may be configured forcommunication over the respective links 434 and 406. In an exemplaryembodiment of the invention, the links 434 and 406 may each compriseless than 100 meters of CAT-5e UTP. Accordingly, the Ethernet PHYs 310 aand 310 b may be configured into a standard Ethernet mode. In thisregard, the network device 400 may function as a network switch, networkcontroller, and/or a router between the devices 432 and 408 and possiblyadditional devices not shown in FIG. 4C. The Ethernet PHYs 310 a and 310b may each communicate over the link 406 at a standard rate as definedby, for example, 10BASE-T, 100BASE-T, 1000BASE-T, or 10GBASE-T, and insome instances may communicate at different rates, which may benon-standard rates.

The protocols and link characteristics described with regard to FIG. 4Bare for illustration purposes and the invention is not so limited. Forexample, both links may be longer than 100 meters and both Ethernet PHYs310 a and 310 b may be configured into an extended reach mode. Also, thenetwork device 400 comprises two PHYs for illustration only and a devicesuch as network device 400 may comprise any number of Ethernet PHYs eachof which may be configurable and/or may communicate over copper, opticalfiber, or backplane.

FIG. 5A is a functional block diagram illustrating a network deviceoperable to convey data between network links having differentcharacteristics, in accordance with an embodiment of the invention.Referring to FIG. 5A, there is shown a network device 500 comprisingEthernet PHYs 310 a and 310 b, MACs 308 a and 308 b, and memory 512. TheEthernet PHYs 310 a and 310 b and the MACs 308 a and 308 b may be asdescribed with respect to FIG. 3.

The memory 512 may comprise suitable logic, circuitry, interfaces,and/or code that may be operable to buffer data being conveyed betweenthe MACs 308 a and 308 b.

In operation, data may be received via one of the Ethernet PHYs 310 aand 310 b and transmitted via the other of the PHYs 310 a and 310 b. ThePHY 310 a may be configured based on characteristics of the link 504 andthe PHY 310 b may be configured based on characteristics of the link504. Accordingly, the rate at which the data is transmitted by one ofthe PHYs 310 a and 310 b may be different than the rate at the data maybe transmitted via the other of the PHYs 310 a and 310 b. For example,the links 502 and 504 may comprise different physical media, comprisedifferent grades of physical media, be different lengths, be coupled todifferent types of network devices, and/or comprise a different numbersof channels. Consequently, as data is received via the Ethernet PHY 310a for transmission via the Ethernet PHY 310 b the different data ratesmay be matched by buffering data in the memory 512.

In an exemplary embodiment of the invention, data may arrive via theEthernet PHY 310 a faster than the Ethernet PHY 310 b may transmit thedata. Consequently, the Ethernet PHY 310 b may utilize CRS 120 b tocontrol the transfer of data from the MAC 308 b to the Ethernet PHY 310b, which in turn may determine the rate at which the MAC 308 b readsdata from the memory 512. Consequently, the memory 512 may eventuallyreach a level or capacity that is beyond a particular threshold and thememory 512 may be unable to receive more data from the MAC 308 a untiladditional data is read from the memory 512 and transmitted by theEthernet PHY 310 b. An indication that the memory 512 is filled abovethe particular threshold may be provided to the MAC 308 a via a signal506 a. Upon detecting that the memory 512 is at a level above theparticular threshold, the MAC 308 a and/or the PHY 310 a may notify thelink partner sending the data. As a result, the link partner may pausetransmission of the data or alter a rate at which it transmits the datato the network device 500. In this manner, the network device 500 may beoperable to utilize a back pressure to control data transmitted to thenetwork device 500 by a link partner. Additional details of controllingtraffic in the network device 500 are described with respect to FIGS. 5Band 5C below.

In one embodiment of the invention, the network device 500 may be aMACSec PHY adapted to convert between two data rates and/or networklinks. In this regard, a second PHY 310 b may be instantiated or coupledto a MACSec PHY such that the MACSec PHY is operable to interface to twonetwork links. In this regard, the network device 500 may beconfigurable to operate as a MACSec PHY or as a converter between twonetwork links. The memory 512 may either be utilized for implementingMACSec protocols or for buffering data to rate match the network link502 and the network link 504.

FIG. 5B is a flow chart illustrating exemplary steps for controllingingress data flow in a network device that conveys data between networklinks having different characteristics, in accordance with an embodimentof the invention. Referring to FIG. 5B, start step 532, the exemplarysteps may advance to step 534. In step 534, it may be determined whetherthe memory 512 is at a level that is above a particular threshold, wherethe threshold may be configurable. In instances that the memory 512 isnot at a level that is above the particular threshold, the exemplarysteps may advance to step 536.

In step 536, the PHY 310 a and MAC 308 a may be configured and/orprepared to receive data. In this regard, in some instances the MAC 308a and/or the PHY 310 a may be enabled to operate in an energy savingmode and in step 536 the MAC 308 a and/or the PHY 310 a may transitionout of the energy saving mode and may be trained and/or synchronizedwith a link partner. Upon receiving data from the link partner, theexemplary steps may advance to step 538.

In step 538 the PHY 310 a may process the received data and convey thereceived data to the MAC 308 a. The MAC 308 a may store the data in thememory 512. Subsequent to step 538, the exemplary steps may advance tostep 534.

Returning to step 534, in instances that the memory 512 is at a capacityor level that is above the particular threshold, the exemplary steps mayadvance to step 540. In step 540, the MAC 308 a and/or 319 a maygenerate one or more signals or otherwise notify link partner(s) topause or slow transmission of data to the network device 500. Subsequentto step 540, the exemplary steps may advance to step 542.

In step 542, the MAC 308 a and/or the PHY 310 a may wait for the memory512 to drain below a particular threshold. In this regard, the durationof the wait may depend on the rate at data from the memory 512 by theMAC 308 b and being transmitted by the PHY 310 b. In some embodiments ofthe invention, portions of the network device 500, such as the MAC 308 aand/or the PHY 308 a, may transition to an energy saving mode duringthis time. Once an amount of data buffered in the memory 512 drops belowthe particular threshold, the exemplary steps may advance to step 544.

In step 544, the MAC 308 a and/or the PHY 310 a may stop applying backpressure to the link partner and/or notify the link partner to resumetransmission of data to the network device 500. Subsequent to step 544,the exemplary steps may advance to step 536.

FIG. 5C is a flow chart illustrating exemplary steps for controllingegress data flow in a network device that conveys data between networklinks having different characteristics, in accordance with an embodimentof the invention. Referring to FIG. 5C, subsequent to start step 542,the exemplary steps may advance to step 544.

In step 544, it may be determined whether there is data to betransmitted that is buffered in the memory 512. In instances that thereis data buffered in the memory 512, the exemplary steps may advance tostep 548. In step 548, it may be determined whether the CRS 120 b isasserted. In instances that CRS 120 b is not asserted, the exemplarysteps may advance to step 552. In step 552, the MAC 308 b may read dataout of the memory 512, process it accordingly, and convey it to the PHY310 b. The PHY 310 b may process the data accordingly and transmit itonto the link 504. Subsequent to step 552, the exemplary steps mayadvance to step 544. Returning to step 548, in instances that CRS 120 bis asserted, the exemplary steps may advance to step 550. In step 550,the MAC 308 b may hold-off or defer reading data from the memory 512 andconveying the data to the PHY 310 b until CRS 120 b is de-asserted. Uponde-assertion of the CRS 120 b, the exemplary steps may advance to step552.

Returning to step 544, in instances that there is no buffered data inthe memory 512, which is pending transmission, the exemplary steps mayadvance to step 546. In step 546 the MAC 308 b and the PHY 310 b mayawait arrival of data to be transmitted. In some embodiments of theinvention, the MAC 308 b, the PHY 310 b, and/or other portions of thenetwork device 500 may be configured to operate in an energy saving modeduring this time.

Various aspects of a method and system for network communications via aconfigurable multi-use Ethernet PHY are provided. In an exemplaryembodiment of the invention, a first Ethernet PHY 310 may be configuredbased on characteristics of a network link 304 over which the firstEthernet PHY 310 communicates, and a rate at which data is conveyed froma first media access controller (MAC) 308 to the first Ethernet PHY 310via a media independent interface (MII) 114 may be controlled via acarrier sense signal 120 of the MII 114. The carrier sense signal 120may be controlled based on a rate at which the first Ethernet PHY 310transmits data over the network link 304. The rate at which the firstEthernet PHY 310 transmits data over the network link 304 may bedetermined by monitoring a queue 115 that buffers data to betransmitted. The carrier sense signal 120 may be asserted when an amountof data stored in the queue 115 is above a threshold.

The carrier sense signal 120 may be de-asserted when the amount of datastored in the queue 115 is below a threshold. The first Ethernet PHY 310may be configured based on a length of the network link 304. The firstEthernet PHY 310 may be configured based on a grade of the network link,where exemplary grades comprise Cat-1 through Cat-7a cable. The firstEthernet PHY 310 may be configured into one of a plurality of modescomprising an Ethernet over digital subscriber line (DSL) mode, anextended reach mode, and a standard Ethernet mode. The MII 114 maycomprise one of a media independent interface (MII), a gigabit MII(GMII), a reduced MII (RMII), reduced gigabit MII (RGMII), and 10gigabit MII (XGMII).

In some embodiments of the invention, a first Ethernet PHY 310 b, afirst MAC 308 b, a second Ethernet PHY 310 a, and a second MAC 308 a maybe integrated within a network device 500. In such embodiments of theinvention, data may be received by the second Ethernet PHY 310 a,buffered in a queue 512, and transmitted by the first Ethernet PHY 310b, where the second Ethernet PHY 310 a may receive the data at a ratedifferent than the rate at which the first Ethernet PHY 310 b transmitsthe data. In some instances, the second Ethernet PHY 310 a may beoperable to request that a link partner pause or slow down transmissionof data based on a status of the queue 512.

Another embodiment of the invention may provide a machine and/orcomputer readable storage and/or medium, having stored thereon, amachine code and/or a computer program having at least one code sectionexecutable by a machine and/or a computer, thereby causing the machineand/or computer to perform the steps as described herein for networkcommunications via a configurable multi-use Ethernet PHY.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputer system, or in a distributed fashion where different elementsare spread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

1. A method for networking, the method comprising: in a first EthernetPHY, said first Ethernet PHY being operable in a plurality of modes, afirst mode of said plurality of modes comprising an Ethernet overdigital subscriber line (DSL) mode, a second mode of said plurality ofmodes comprising a mode in which said first Ethernet PHY communicatesover a cable that is 100 meters or less in length, and third mode ofsaid plurality of mods comprising a mode in which said first EthernetPHY communicates over a cable that is longer than 100 meters:determining characteristics of a cable over which said first EthernetPHY communicates; selecting, during operation of said first EthernetPHY, one of said first mode, said second mode, and said third mode basedon said determined characteristics; and controlling a rate at which datais conveyed from a first media access controller (MAC) to said firstEthernet PHY via a first media independent interface (MII) bycontrolling a carrier sense signal of said first MII based on a rate atwhich said first Ethernet PHY transmits data over said cable.
 2. Themethod according to claim 1, comprising monitoring a queue that buffersdata to be transmitted by said first Ethernet PHY to determine said rateat which said first Ethernet PHY transmits data over said cable.
 3. Themethod according to claim 2, comprising asserting said carrier sensesignal when an amount of data stored in said queue is above a threshold.4. The method according to claim 2, comprising de-asserting said carriersense signal when an amount of data stored in said queue is below athreshold.
 5. The method according to claim 1, wherein saidcharacteristics comprise a length of said cable.
 6. The method accordingto claim 1, wherein: said characteristics comprise a grade of saidcable; said grade comprises one of: category 1 cable, category 2 cable,category 3 cable, category 4 cable, category 5 cable, category 5e cable,category 6 cable, category 6a cable, category 7 cable, and category 7acable.
 7. The method according to claim 1, wherein said first MIIcomprises one of a media independent interface (MII), a gigabit MII(GMII), a reduced MII (RMII), reduced gigabit MII (RGMII), and 10gigabit MII (XGMII).
 8. The method according to claim 1, wherein: saidfirst Ethernet PHY, said first MAC, a second Ethernet PHY, and a secondMAC are integrated within a network device; and said data is received bysaid second Ethernet PHY, buffered in a queue, and transmitted by saidfirst Ethernet PHY, wherein said second Ethernet PHY receives said dataat a rate different than said rate at which said first Ethernet PHYtransmits said data.
 9. The method according to claim 8, wherein saidsecond Ethernet PHY requests that a link partner pause or slow downtransmission of said data when said queue filled above a threshold. 10.A system for networking, the system comprising: one or more circuits foruse in a first Ethernet PHY, said one or more circuits being operable ina plurality of modes, a first mode of said plurality of modes comprisingan Ethernet over digital subscriber line (DSL) mode, a second mode ofsaid plurality of modes comprising a mode in which said first EthernetPHY communicates over a cable that is 100 meters or less in length, andthird mode of said plurality of modes comprising a mode in which saidfirst Ethernet PHY communicates over a cable that is longer than 100meters, and said one or more circuits are operable to: determinecharacteristics of cable over which said first Ethernet PHYcommunicates; select, during operation of said first Ethernet PHY, oneof said first mode, said second mode, and said third mode based on saiddetermined characteristics; and control a rate at which data is conveyedfrom a first media access controller (MAC) to said first Ethernet PHYvia a first media independent interface (MII) by controlling a carriersense signal of said first MII based on a rate at which said firstEthernet PHY transmits data over said cable.
 11. The system according toclaim 10, wherein said one or more circuits are operable to monitor aqueue that buffers data to be transmitted by said first Ethernet PHY todetermine said rate at which said first Ethernet PHY transmits data oversaid cable.
 12. The system according to claim 11, wherein said one ormore circuits are operable to assert said carrier sense signal when anamount of data stored in said queue is above a threshold.
 13. The systemaccording to claim 11, wherein said one or more circuits are operable tode-assert said carrier sense signal when an amount of data stored insaid queue is below a threshold.
 14. The system according to claim 10,wherein said characteristics comprise a length of said cable.
 15. Thesystem according to claim 10, wherein: said characteristics comprise agrade of said cable; said grade comprises one of: category 1 cable,category 2 cable, category 3 cable, category 4 cable, category 5 cable,category 5e cable, category 6 cable, category 6a cable, category 7cable, and category 7a cable.
 16. The system according to claim 10,wherein said first MII comprises one of a media independent interface(MII), a gigabit MII (GMII), a reduced MII (RMII), reduced gigabit MII(RGMII), and 10 gigabit MII (XGMII).
 17. The system according to claim10, wherein: said first Ethernet PHY, said first MAC, a second EthernetPHY, and a second MAC are integrated within a network device; and saiddata is received by said second Ethernet PHY, buffered in a queue, andtransmitted by said first Ethernet PHY, wherein said second Ethernet PHYreceives said data at a rate different than said rate at which saidfirst Ethernet PHY transmits said data.
 18. The system according toclaim 17, wherein said second Ethernet PHY requests that a link partnerpause or slow down transmission of said data when said queue filledabove a threshold.
 19. A method for networking, the method comprising:in a first Ethernet PHY, said first Ethernet PHY being operable in aplurality of modes, a first mode of said plurality of modes comprisingan Ethernet over digital subscriber line (DSL) mode, a second mode ofsaid plurality of modes comprising a mode in which said first EthernetPHY communicates over a cable that is 100 meters or less in length, andthird mode of said plurality of modes comprising a mode in which saidfirst Ethernet PHY communicates over a cable that is longer than 100meters: determining characteristics of a cable over which said firstEthernet PHY communicates; selecting, during operation of said firstEthernet PHY, one of said first mode, said second mode, and said thirdmode based on said determined characteristics; and controlling a rate atwhich data is conveyed from a first media access controller (MAC) tosaid first Ethernet PHY via a first media independent interface (MII) bygenerating and sending pause frames from said first Ethernet PHY to saidfirst MAC based on a rate at which said first Ethernet PHY transmitsdata over said cable.